Manufacture of paper and the like



Patented. Apr. 2, 1935 v 1,996,707

MANUFACTURE OF PAPER AND THE LIKE Alexander Nathansohm Berlin-Wilmersdorf, Germany No Drawing. Application May 31, 1930, Serial No. 458,909. In Germany June "I, 1929 Claims. (01. 92-21) 'In my copending application, Serial No. 443,633, kind, becomes completely impermeable to water filed April 11, 1930,'I have described and claimed and remains so even when the reagent has been textile material treated with an esterifying derivaextracted again by a suitable solvent. tive of a higher. fatty acid under conditions as The products treated thus offer no visible dif- 5 herein described to produce mild esterification, ference' from the material non-treated, and no 5 and the method of producing such material. appreciable increase of weight is detected by The water absorbing property, which is-peculiar weighing before and after the treatment; neverto paper pulp, is characteristic even of the finished theless, the faculty of absorbing water is comfabrics made from same,-as paper, millboard, and pletely lost. Even the thinnest sheet is repellent the like, especially wall board, if it is not supto water. Organic liquids, as alcohoLare ab- 10 pressed by certain definite means. The impregsorbed as before. nation of paper is a means of that kind. It is Itisreally surprising how mildatreatment may. old to incorporate resin' andalumina into the succeed in producing the desired effect. To give paper pulp to waterproof the same. In that way an example, a few hours treatment with a warm ll! the water absorbing propensity of the cellulose 2-5 per cent solution of stearic anhydride is sufii- I mass is reduced to such a point that ink, for incient with any paper. with a more reactive stance, is but slowly absorbed during the process paper, good grade filter paper for instance, it is of writing. It is impossible, however, to obtain sufiicient to soak the material in a very dilute, complete impermeability to water in that A way. say 0.1 to 2 percent solution of stearic or palmitic To effect complete impermeability in certain anhydride and to dry it. After staying a few 20 cases, it has been usual to soak paper in soluhours at ordinary temperature the paper has betions of stearic acid, wax, rosin and the like, to come water repellent. Even if soaked in benzin allow the solvent to evaporate and thereby to for a number of days, a paper treated in that incorporate the solute in the paper. By such a way remains to be impermeable to water, by con- '25 treatment, one succeeds tomake paper and the trast to a paper imbued in the old way by a like completely impermeable to water, but it is solution of stearic acid. necessary to incorporate a considerable quantity In the manner described the process can be of the substances mentioned-into the pulp, which applied at any stage of the manufacture or materially and in different ways impairs the finishing process of paper, at which the fibre original properties of the paper. The paper turns i in a dry condition. As an example, dry boards 0 hard and brittle and can be used only to a limited of cellulose, which may or may. not be ground extent as a packing material, which should be r t purpose r fi di n rify n hlits chief use. tion, the excess of the esterifying agent is washed The object of this invention is a new process, away, the wash liquor is removed, whereupon the which serves to make paper and the like immaterial is worked in the usual manner. 35

permeable to water without any change of its Alternatively, the finished renning band of remaining physical and technicalqualities. The paper, millboard and the e, ufl ei y dried, process was developed from the fact found by is treated as disclosed heretofore; or paper and me, that a trifling amount of a water repellent the like, which has been subjected to the action- 40 radical is suflicient to obtain the desired eifect,. of sulphuric. acid, or of zinc chloride, or to 40 provided that it be embodied into the paper mass coloring, or to any other similar finishing procby treating with esterifying derivatives of higher ess, is treated in the same way.

- .fatty acids. By the term higher fatty acids I There is, however, still another way of carmean those fatty acids which contain ten or more 'ying out this invention, which consists of add- C-atoms in each molecule, for instance capric g the esterifyine reagent o the fib ous mass 45 acid, stearic acid, palinitic acid, oleic acid, men not as a solution, but as an emulsion. The tanic acid, and the like. According to this prinydl s of acids are especially a p o ciple the paper is treated, neither with a free be worked into emulsions, in h methods acid, like stearic or abietic acid, nor with an familiar from the manufacture of fatty mulester, similar to those contained in wax, as has sions. By this modification, the invention can 5 been done previously, but it is treated with an be applied at a y st e of t e pap a d m esterifier, such as a chlorid, or an anhydride board manufacturing process, because, in that of one or more of the higher fatty acids. Very case, it is not required that the fiber be dry. surprisingly, it has been found that paper and An advantageous W y Of yin ut Jihi inthe like, when treated with reagents of the said vention consists of first treating the fibrous mass 5;

with a suitable derivative of an acid, for instance with the anhydride of a higher fatty acid, to be applied either as a solution or as an emulsion, then drying and finally exposing the dry product to a temperature exceeding 35 C., preferably to a temperature between and 110 C. The time required to secure a satisfactory effect is different for different materials. While for a cellulose product two to three hours are sufficient, other matter, for instance such containing wood pulp, is preferably treated, to obtain the maximum effect, for six or more hours at the said temperature. This modification of my process is especially to be recommended in case that an emulsion of stearic or palmitic anhydride is added to the wet fibrous mass, as explained heretofore, whereupon the said mass is worked, in the usual way, into paper or millboard and the product is dried and treated at an elevated temperature as said.

As an example, water repellent cable paper is made by soaking ordinary cable paper in a one wood pulp together with a three percent emulsion of stearic anhydride in ammonia water, to which a little starch paste has been added, using the emulsions in the proportion of one part, by weight, of stearic anhydride to one hundred parts of ground wood. The mass is worked into millboard on a boarding machine and the dry millboard is treated at about C. during six hours. A product is obtained, which does not absorb water and which is excellently suited as a packing and as a building material.

Instead of palmitic or stearic anhydrides one can use for instance lauric, palmitic, oleic, montanic anhydrides or the like, or mixtures of different anhydrides. I

A very important application of this inven-' tion consists of manufacturing paper and millboard, which are water repellent and fireproof at the same time. Fireproof paper and the like has of course, been made before, by soaking the material with strong solutions of different salts, for instance of ammonium chloride. Such products are, however, a great deal more liable to absorb water, than even ordinary paper and millboard are. In many cases, especially for building purposes, they can hardly be used. On the other hand, paper and millboard made water repelling by known methods, cannot be made, by a combined process, fireproof at the same time. They either do not absorb the salt solutions, or, if the solution is forced into them by heat, the water repelling effect is destroyed.

The products made waterproof according to the method here disclosed, have the peculiarity, though they repel cold water, to admit warm water to a degree which rises with temperature. After drying, they repulse coldwater again as before. By virtue of that peculiarity, paper, millboard and the like can be made waterproof and fireproof at the same time. This is done by first making the product waterproof in any manner as explained heretofore, then steeping it, at an elevated temperature, preferably above 40 0., into a salt solution of the same kind as usually employed for the purpose.

As an example, waterproof wallboard is made by adding, to wood pulp suspended in a board mill cylinder, a three percent aqueous suspension of stearyl anhydride, using one part by weight of the anhydride to one hundred parts of dry paper pulp. The board obtained is dried, for six hours, at a temperature of 90 C., and is finally soaked in a solution, which contains grams of ammonium chloride and 50 grams of sodium tungstate in 1000 cc. ter having been dried, the millboard thus made is water repellent and fire retarding at the same time.

As used in the claims, the term paper material includes only paper pulp and finished paper.

I claim:

1. A process for waterproofing paper which comprises treating the said paper with an esterifying derivative of a higher fatty acid, and drying the product at a temperature above 35 C.

2. A process for waterand fireproofing paper which comprises treating the said paper with an esterifying derivative of a higher fatty acid, then steeping the said paper in a solution containing a fire-retarding salt.

3. As a new article of manufacture awaterproof paper material being the product obtained by treating the said paper material with an esterifying derivative of a higher fatty acid, and drying the product at a temperature above 35 C.

4. As a new articleof manufacture a fireand waterproof paper material being the product obtained by treating the said paper material with an esterifying derivative of a higher fatty acid, then steeping in a solution containing a fire- -retarding salt and drying the product at a temperature above 35 C.

5. A process for waterproofing paper pulp which comprises treating the said pulp with an esterifying derivative of a higher fatty acid, and subjecting the material after drying to a temperature of more than 35 C. for at least one hour.

ALEXANDER NATHANSOHN. 

